1. Field of the Invention
This invention generally relates to automatic font changing apparatus. More specifically, this invention deals with apparatus to be included under the cover of a daisy wheel printer which utilizes a print element housed in a cartridge during printing. The apparatus is adapted to effect an automatic exchange of print elements in the cartridge.
2. Description of the Prior Art (Prior Art Statement)
Representative of the closest known prior art are the above cross-referenced application Ser. No. 098,288, of Dollenmayer, and U.S. Pat. No. 4,026,403 to Inose et al.
In the Dollenmayer application is disclosed an under-the-cover font changer for a daisy wheel printer. The font changer includes a swing-away print element carrying rack. The rack is positionable such that carried extra print elements are stored in a horizontal position under a platen during a printing operation. For a print element change, the rack is swung upward and toward a selection motor drive shaft. The upward swing of the rack is to bring the print elements into a vertical position. Also disclosed is the translation of selection motor toward and away from the rack for a print element change. The functional similarities between the two applications are the use of a rack to position a print element for a print element change, and translation of a selection motor to effect a print element change. Structurally though, there are many differences. The most important as related to the instant application are that (1) extra print elements are mounted on a rack which is vertically oriented and positionable for loading and unloading a print element into, and out of a print element cartridge, (2) a spring means is included in the cartridge for cooperating with a translatable selection motor for facilitating unloading and loading of a print element, and (3) a latch mechanism is connected to the rack and operable by the cartridge upon elevating and lowering the rack for maintaining print elements on the rack when absent from the cartridge.
In U.S. Pat. No. 4,026,403 there is disclosed an under-the-cover carousel type font changer for a daisy wheel printer. Other than the fact that the font changer can be mounted under the cover, the structure disclosed is totally different than that of the instant application.
U.S. Pat. Nos. 3,892,303 and 3,645,372, and IBM Technical Disclosure Bulletin Vol. 13, No. 5, October 1970, page 1149, are representative of other known art related to automatic font changers. Since these patents and the IBM TDB are considered to represent no better art than that described above, no further explanation is deemed necessary.